Automatic grinding mill



Aug. 3 1926. v A; SCHR AUTOMATIC G RINDING MILL l l jizz/@71h70.-

Filed Feb. 2OI .1925

Aug. 3` ,1926. 1,594,633

.Y Ain. SCHR Au'rpu'rrc GRI-mame MILL Filed Feb. 20. 1925 11 sheeis-she'et-;

Aug. 3,1926.

Au'ronlmrc GHIDING MILL l I.

Filed Feb. 20. 1925 11 sheets-.shqtb juve @Zar Aug. 3 ,'1926.

A. scHR -Au'ronuc @alumna u ILL Filed Feb. 20, 1925 11 Sheets-Shi 10 o. Hi

Alm 3.

SICHR vMmolwl'uc GRI'NDING MILL Filed Feb. 20, 1925 11 sheets-sheet 11 lllllllulllllllllllllllllllllllllllll li Q Patented Aug, 3, 192i nur ran stares ALFRED sc'nln, or GossAU, SWITZERLAND.

AUTOMATIC eninnine MILL. y,

Application mea February 2o, 1925, serial No. 10,590, and in switzerland Aprii 17,1924.:-V l

grinding mill for domestic use to which thek uncleaned wheat is supplied and the iinished tlour and brans are delivered into bags without :involving any manual labour during4 this conversion.' v Y Automatic mills for do-mestic use have al ready been proposed. .kl-lowevei, they have the drawback that although they work automatically they do not produce ailour of the saine quality as produced by thelarge mills. A flour of this quality requires the use oi a large number of grinding passes and sifting means, and the self-contained automatic Vmill according to the present invention Vis so designed that it ispossible to house lall the means forl providing the required nurnber of grinding passes,so that the automatic mill is of a size which permits its use 'tor coniestic .purposes, and yet produces a flour that equals that obtained. in large mills. A mill of this type-is of particular importance for. farmers, who are thereby enabled to produce their own'tlour and oi a quality which only a large mill has hitherto been able to supply.

rlhe self-contained automatic grinding.

mill according to the presentfiiivention comprises a number of cooperating cylinder grinding surfaces for rough grinding, a number oit cooperating cylinder grinding surfaces for negrinding, and a firstv set oit' sitting means arranged above and cooperating with the rough grinding cylinder surfaces and a Second set of sifting means. arranged above the tine grinding surfaces.

Further meansare provided tor conducting the material to he ground consecutively to said individual cylinder grinding surfaces 'for rough and for tine grinding and to and 'troni said sitting means, said means includ-` ing a number oi elevators arranged between rough grinding rolls and the line grinding rolls and to which the material leaving said individual cylinder grinding surfaces is conducted and which deliver said material to said siftingmeans. These sitting means are arranged on both sides of the elevators, whereby a pluralityof grinding. passes are provided in a mill that requires a minimum of space. Y

@ther features oi the automatic mill will of a constructional example.

i IV-IV in Fig. 1,

f and 4 The automatic mill according to thepresinvention isillustrated bywa'yfof exampleV on the accompanying drawings, lin vshichcf Fig. 1 isa front'elevationfof theV auto matic millsfwith parts shownin section, i

Fig. 2 is a side elevation Vseen from the right hand lside of Fig. 1, l 7 1 Fig. 3 is aside elevation seen ftrom the vlett hand side ot' Fig. 1 and'` showing'the` drive of various parts of Vthe automatic mill, .p f l Fig, 4 is a vertical section along line Figf is a vertical section along line V-V rin Fig. 4,

Fig. `5a is a horizontal sectionvoi` a detail, i

*Fig 6 is a vertical section alcng line Vl-VI in Fig..4, Y p Y Fig. 7 .is a vertical section along line VlI-j-VII inl Fig. 4, Y

Fig. 8 isa horizontal sectionV alongline VH1- Villain Fig. 4, y y

Fig. 9 isa horizontal sectionalongline IKW-IX in Fig. 4,

Fig. 10 shows a Figs. `14-16l show theparts'used for `feed-V ing the stripping machine lin vertical section,

xvii-xvii in riginrig. is Shows deans of theater', macias.;

nism in a verticalsectionand ings 1 rollers of vthe rough grinding device and 3 are the cooperating smooth rollers or the tine grinding device. The rollers 2 f and4 are rotated at a higher speed than the The'sha'ts 5 and 6 ci the lower quickv running rollers 2 and 4 arek rollers 1 and 3.

mounted in fixed b'racketbearings and 8 eren-if i part of the mill ina vertical section along'line 'X-X'in Fig. i9,

Fig. 17 is a vertical section along'` line i ig. 19 is a diagram showingthe various passages oi the material to be ground in theV Y automaticmill. ReferringV now to the drawand@ denote the cooperating luted` respectively (Fig. 2) and the'shaits and l 10 of the upper rollers 1 and 3 'arevmcunted in bracket bearings 11 and 12 swingably arranged about pivots 13 and 14 respectively. The bearings 11 and 12 respectively are i'csiliently held in position by means of theV 'angst and e.

springs 15, 16and 17, 18 respectively; handwheels 19 and 20 cooperating with nuts 21, 22 on the ends ofscrew threaded bolts 23 and 24 serve to adjust the distance be tween the shafts 5 and 9 and 6 and 10 respectively whereby the distance between fthe Y circumference of the cooperatingrollers Y1 and 2 and 3 and'4 respectively can `be ad# The pair of rollers v1 and2`isisubdivided the longitudinal direction finto seven indivldualpairs Vof roller surfaces 27, 28,29,Y

30, 31, 32 and33 (/Fig.16)1 forming seven different passages and the fineness o'f fthe fliiting increases `Vfrom the vpair ofv roller surfaces 27--to Partition Vwalls 34, 35, 36, .37, 38 and 39k separate these passages from each other.

4The'pair orrollers3and f4for .tine grinding is subdivided into'tive'individual pairs of roller surfaces 40, 41, A'42, 43"an d 44,

` 'forming 'five `passages for fine grinding,

which passages are separated `from f each other `by the partition "walls 45, 46, 47 and 48. j n 'f The drive of theautoin'aticimill is` effected by .means of amain driving=pulley 49 (Fig.

" V1) iixedto shortpiece of shaft 50 mounted -in'bearings 51 and `52.y To the shaft 50 a chain wheel 53"(Fig. andla'gearwheel 54 are fixed, the latter cooperating with a gear wheel"55 ona short counter shaft 56; fT rotation of the roller shaft 'is obtained by a chain wheel 57 'fixed to said shaftV and a chain 58 'operatively connecting the chain wheels 54 and'57. furtherchain wim-e159 is fixed to the shaft 5 andcooperates withla chain wheel-60 Afixed 'onjth'erroller shaft 10 by meansof the chainA 61, wherebyjrotation Vis 'imparted'.to the shaftf10lan'd thereb to the roller 3. '0n the countersh'aft'56 ac ain wheel 62 is fixed lwhich `cooperates with a chainwheel I64-`onthe rollershaft 6 through ith-e vintermediary ofthe'chain'565 and the rollershaft 9 is driven'fryomthe roller shaft 6 by means ofthe chain-'66 vandthe chain wheels 63`Yand 67. y

chain wheel 68 on the shaft 6- drives by the` chain69-'a chainl ywheel 70 on a shaftA l 71. 'On theshaft 102 a screwwhe'el72 (Figs.

',154 and 17) is fixed 'as well as a crank pin 73.

Thejscre'w wheel -72 isin mesh with a` screw wheel 74 on `a shaft 75 land a screw 'wheel 76 fixed to `a. shaft 77 "cooperates with the screw wheel7`6 -Abevelwheel 7 8vis fixed to theV shaftV 77 and islin mesh with Vaf'bevel wheel 79 on averticalv shaft 80 ofay stripping ydev-ice. The latter comprises 'verticai beaters and 108 and chain and '117 'from'each other (Fig."18).

The husks of the grain pass, through the druinfand vleave the mill at the aperture 83 and the stripped grain leaves at the bottom of `the vdrum 82 and vpasses Vinto the channel 84.

y The materialrtobe fgrou1id,-i.e.-the grain, is fed into the hopper 85 from where it passes a preliminarysievef86,`by which the large sized Vimpurities are separated 'which leave at 8,7, and lthe ymaterial passing the 'sieve 86 drops on a further sieve 88 through .81..by which the grain `is piojectedagainst a perforated kdrum 82 in the known manner.

which'sand and otherimpurities pass.- The n sieves 86 and 88 Aareis'haken to and fro jfrom the crank pin 73 anda connecting rod 89 and are suspended on plate springs 90 4and 91.

VThe sand-passing throu-ghfthesieve '88 is deviatedA by partition walls such as'92 (Fig. 16) and leaves at l83,'and the grain, which vided, into' the attore-mentioned stripping de- "vice 81,-V 82.

`'irb'ove the: rough grindingrollers 1', y2 and the' line; grinding rollers 3,"4s1fte`rs 95, 96, 97 and98are(arranged which consist of a circu 103, 104 and 71 of the-siftei's 96,97 and 98. The shaftv 104 is rotated by means of `a chain'105 and'chain wheels 5106 and 7 0 -from :thegshaft 71V and to the shafts 102-and 103 rotation is iinpaited by means of .chains S107 wheel's-109, 109 and 110 (seeFig. v3)'.v

. 1nFi'g. 18.'thesifters 97 andi 98. are shown "in la vertical section from which it may be 'seenfthat the sifter 97 is subdivided and consists of four individual 'sifters 111, 112, 113 Y a'nd91141 and fthe sifter "98. consists of three individual sifters v115,116 'and rv117 1n a similar' mannerthesifter 96 is subdivided into four individual sifters 118, 119, 120 and 121 and the 'sifter 95 consists also of four indi- Y'vidual VVsift'ers i122, 123, 124 and 125 -as is iindicated in-iFig. 119. The sifters 111, 112, -113 and 1'14jare'subdivided by partition ywalls 126,127 and 128 andpartition'walls- 129, and 130 separate Vthe sifters y115,116 The .85 'lis retained-bythe sieve '88 passes through` 'thelduct 93, in which a magnet 94 1s pro- 'lar `casing 99on`e`portionof which isformed by -a sieve`100- 'Insidefthe casing a number of blades l101 are' continuously rotating about lthe shafts 102 of thesifter 95 ortheshafts partly crushed orground material consisting i of semolina or -a mixture of meal and'semolinato be siftedentersthe si'fter111 through Y.

the aperture'131:arranged at one end of the 'siften y The material whichdoes not passy thesi'evef100 leaves the sifter 111 through 'lthe aperture 132 'arranged'l at the'l opposite end of kthe sifter. Similar inlet openings 133, 134, 135, 136, `137 and 138 and Outlet openings-139-144 areprovidedin the sifters i12-'117 (Figs. v7 and V18'). The correspondin@` inlet o eninos inthe .siftersfl18-v-125 `are a o y l in each sitter consists of a number of Vsingle parts 101 (Fig. 18) arranged at an anglek vvto the axis ot rotation oi Lne blades whereby the material inside the sitter is moved from the inlet end towards the discharge end.

The material is delivered to the individual sitters by means of bucket elevators ot which iteeii are provided arranged be side eachV other. Oi `these the elevators 161-169 (Figs. 8 and 19) discharge towards the sitters 118 125 land theelevators l-175 discharge' towards the sitters 111-117. rlhe cooperation ot every single elevator with the single sitters will be ex plained later on with reference to Fig.y 19 which shows a diagram oi? the various passages of the material automatically occurring within the mill. The elevators are driven by imparting rotation to their upper pulleyshat'ts 176 and 177. To this end a -chain pulley V178 is fixed to the shaft 177 and a chain 179 transmits the driving power troni the shaft 103. A-pair ot meshing spur gear wheels 180 andv V181 is interposed between the shafts 176 and 177. Each elevator'is enclosed in` a Vcasing 'and it receives the material to be raised to the to-p or the niill from one'o'll the individual rough grinding i'ollersor line griiiding rollers or from another sourcevas will vbe explained hereinafter with reference to Y the diagram shown in Fig. 19. Asis shown s Ain Figs. 6, 7 and 9 for instance theV material passing through the roughfgrinding passage 27 is supplied to the elevator 161 through an opening' 182; the elevator 162 receives the material which has passed the stripping devico`81, 82 through 'the chute 84 and the opening 183; the 'elevator 163 receives the material leaving the rough` grinding passage 28 through the chute 184; the elevator 164 receives the material from the rough grinding rollers 29 through the chute 185, to the elevators 165, 166 and 167 material is supplied' from the roller passages 30, 31 and 32 through the chutes 186, 187 and 188; the el- 4evators 170, 171, 172, 17 3 and 17 5 are fed by the material tronii the tine grinding roller passages 44, 43, 42, 41 and 40 respectively through the chutes 189, 190, 191,192 and 193 respectively, the elevator 174 is supplied with material through chuteA 194 coming` The elevator 169 re`- eci-oss the whole width ot the mill troni where it passes through thechutes 198, 195 to the'elevator 169 10). The screw conveyor 197 is driven from the shatt 9 byy means of the chain 199 and the chain wheel 200. conveyors 201 and 202 are arranged which receive the material which passesV the sieve parts 100 of some of the individual sitters 111-117. They material discharged bythe screw conveyors 201 and 202 is the nished :meal obtained in two yqualities and leaves the mill at the discharge openings 203 and 204 (Figs. 1 and 2) to be lifillediinto bags The convey/'0112.201 `is driven from the shaftlO by means of thechain 205 and chain wheels 206 and 206 (Fig. 3) and the conveyor 202 Ais in driving connectionwith the conveyor 201 vby the pair ot cooperatingigear wheels 207 and `208 (Fig. 9).

n 209 denotes a. feed rollerarranged above vthe line grindingroller 3, a small roller 210 cooperates with` the roller 209. The latter is` driven bythe aid oia chain wheel `21,1

Below the sifters97, 98 two screw.k

and a chain`212 froin'the chain wheel 211(V ,y

on the shaft ot the screw conveyor 201.

lnorder to keep clean the sieve parts v Y oi" the sitters. 97 and 98 brushes 213 are pro-VV vided which are in. cont-act with the sieve parts-100 and are mounted oira traine-214 (Fig. 4). VGn the latter iurther brushes i 215 arepiovided which cooperate with windows 216. The frame 214 isiixed toa rod `217 extending across the: whole width ot' the mill. `rllhe rod 217 can be reciprocated longitudinally `in the bearings 218 andatoand iro in'ovementis impartedv to the rod by means ofva connecting rod 219 and crank 220. .',lhe latter is rotated, Fig. 1, by means of a worm wheel1221 coo-peratingwith a worin 222. The drive of the worm iset tec-ted by appair of gear wheels 223, 224,

:chain wheels 225, 220, IChain 227 from a counterlshatt 228. `The latte-r drives by 'means of l Pali' .0f gear wheels 229 and 230 a shaft 231- and is' driven fromthe elevator shaft 177 through the interposition of chain wheels`232, 233 and chain 234,'of a trainot gear wheels 235, 236, 237 and 238, the chain wheels 239 and 24U- and chain 241 as is f yinent. These shaking sieves (Figsr4 and 5) are enclosed in a Vchest 243 arranged at one side ot the inillcasing 25. sieves 244 and 245 slightly inclined. against thel horizontal and arranged beside each other at different elevations and `mounted in a box 246 which is suspendedon two plate springs 247 and 248;y Above the sieves a trough 249 is arranged `through which other material is discharged at its lower end There are twoias which leaves the chest 24H-Sat theopening Y 250. The material which passes through the sieves 244 and 245 drops on a bottomv cleaned `by a .251 and passes through 'an Aopening 252 ,of the latter from where it gets down a chute the bottom 255` toa chute 256 and thereby to the elevator' 166. The shaking motion of the chest 246'and thereby .of the sieves 244 and 245 is eiiectedfby means of a connectingrod 257, V and cranl; gear 258 which lis rotated by the aid ot screw Wheeis '259,

260, chain wheels 261, 262 and chain 268 from theshalft of the screw conveyor 197 The sieves 244` and 245 may be known travelling brush 264 diagrammaticallyindicated in lFigs. 4 and iand supported by a sieve 244.

Above the stripping 'device (Figs. 16 rand A17) abran brushing device is arrangedconsisting ot' a circular peritorated'drum 265 in which brushes 266 whichare in Contact with lthe drum 265 are rotated byl the shaft 75. s

fhotiairffrom the interior ot the mill to the r hose Vfilters, one chute 807 `being provided y for. every7 two hose filters.,

The material is ied through the opening 267 fronrftheA outlet opening 144 out the Vsitter 117. `The material passing the drum. sieve Q65 is discharged from the mill tl'n'ough plant isthe following z the openino` 268 fand the vmaterial which doesV not pass the drum vleaves the latter lat the opening 269 andis discharged at 270.

In order 'to' convey the latter lmaterialby,

- means of the'brushes to the opening 269 arvnumber of hose filters.

ranged at one end of the,drunnthebrushes consist of individual parts 266 which are placed .obliquely to Vthe direction ofthe axis Vof rotation of thevbrushes.

In order to remove the'hot air generated inside the mill an exhaust fan 271 `is 1arranged onl the top of the chest v25. Rotation is imparted to the Jfan 271'trom the shaft 104 (Fig. 8) by means of the'chain wheels 27 2, 27 8 `and the chain 274. Toprevent dust from being discharged the fan two chests 275 and 276 are provided on the top of the chest 25,fwhich containa There are eight iilter cylinders 277-284 `provided in each ot the chests 2.75 and` 27 67 theen'd hose 277 and 284 Vare in coinpartmen'tsto themselves, 285 and .286 and the remaining six hose 'arearranged in pairs VWithin thevchambers 287, 288 and289 (Figs'l and 4), The inner part ofthe chests 275 and 276 is sube dividedby a horizontal partition wall into anupper compartment 290'and a lower com' Y .partment 291 (Fig. 4). `Inside the compartments 290 the mechanism for Vshaking the hose filters is arranged Awhich consists of the shaft 281 inthe chest 276 'andthe shaft v242 in lthey chest 27 5 on `which shafts cam .turnable kabout .295; a compression spring 296 acts on the vertical yarm'olt said lever and ,causes a tightening of the hosein their longitudinal Vdirection; yVith the-free end .oi the vertical arm of the lever 294 two teetlr297 -and298 on the camvdisc298 cooperate. Furtheracam tace 299 yis provided on-one side oi' the cam disc 298 whichk 'aee cooperates with apin 800` iiXed to a gate 801 pivotedfat 802. The gate 801 con trols an'openingf808 provided .between the compartments in which/the hose filters are llocated and the compartment 291. A. detail of the gates 801, which are held in their open kposition f by tension Vsprings 80.4, kis

Vshown in Fig. 18.l VFurther a .Conduit805 4passes througl'i the compartment 291 vand yconnects thev compartments .in which, the

hose iilte'r are `located with the surrounding atmosphere. 'The y'flow ot" air through said conduits is also controlled by the gates 801.-` The lower open ends of the hose are Vconnected to openings 806 (Fig. 4) leading yto chutes 807 returnmgthe meal collected- 3nthehose-to the elevators; the chutes serve.

at-"thefs'ametime as conduitsgtor leading the -The operation of the above described filter The suction side of partments .291/The warm air yis sucked [from -they interior vof the mill through the hose filters inthose compartments in which the gate 801 has not closed the opening 808.l TheV dust and meal contained inthe f air is deposited in the hose iilters. In order toicleanthe filters the teeth 297 and 298 of :the rotating cam disc 298 act uponthe vertical arm of the two armed lever 294 where- Iby the-hose is slack'ened and thespring 296 themfan' 271 is con` nected bythe ,conduit 808 with the coni-- p is compressed.' When. the end of the lever c .that the `cleaning of the various hose filtersoccurs consecutively. p

Now'the passageswhich.the'grain has to take-within the mill shall be explained with reference to the diagram illustrated in Fig.

The kgrain is filled intothe hopper 85 and vhas to pass'throughthe sieve'86 and along -thesieve '88; The coarse impurities arefdis- V charged at 87 and the sand and smallmatter passing through the sieve 88 are discharged i arm glides'oii a tooth the compressed spring `suddenly turns the lever 294 inthe upward Cil (Fig. 6) to the elevator 161.

. Crushed.

(Figs. 5and 9) into'the elevator 162. rThe latter litts lthe grain to the topot the mill and discharges it into the chute 309 6) whereby it is delivered to the rough grinding rollers 27, and atter being preliininarily crushed therebyV it passes the chute` 182 rlhe latter discharges the material through the opening 145 into the sitter 118 and the part ot the material which doesy not pass the sieve ot 4the shitter 118 leaves the latter atVV the opening 153 and talls dovvn `to be crushed a second time by the rollers 28. On leaving the latter it passes through the chute 184 and getsto the elevator 163 by which it is discharged into theinlet open-` ing 149.0t the sitter 122. The part otthe material which is still in the state ot a coarse Vseinolina and which does not pass through the sieve ot the sitter is discharged at 157 and is turther treated by the rollers 29, and talls thereafter through the chute 185 tothe elevator 164. The latter delivers the material to the inlet opening 146 ot the sitter 119, the coarser parts leave the latter at the discharge opening 154 tromv Where they pass to the rollers30vto be turther Then the material talling down the 4chute 186 is raisedby'the` elevator 165 and delivered through the opening 150 to the sitter 123. The parts which do not pass the sieve ot'the sitter are discharged `at 158 onto the rollers 31, leave the latter through the chute 187 to be raised by the elevator Y 166 which delivers it` through the opening A 147 into the sitterV 120. The material leav-l ing the latter at 155 is noiv crushed a sixth time by the rollers 32, and 'gets by Way ot the chute 188 to the elevator 167 Which delivers it through 151' into they sitter 124.

The material leaving the sitterW through 159 consists solely ot .branl and is delivered through the chute 310 (Fig. 5)Y to the trough 249 trom vvhereit is directly ted into bags M250. f

The finer semolinas whichV havev passed through the sieves ot the sittersv 118, 119,

120, 122, 123 and 124 tall into the screw conveyor 197 (see Fig. 4) trom which they are delivered to the chutes 198 10) and 195 and thereby to the conveyor169 vvliiclrtlischarges this material at 148 into the sitter The `material Which does not pass through the sieve ot the sitter leaves the 4latter at 156 and enters directly the lovver sitter` 125 at 152 `(Fig. 6) and is discharged `at 160 down a chute 311 (Fig. 5) to the shaking sieve 244. The material travelling along the sieve 244 gets into the chute/256 to the `elevator 166l (Figrll, which Vandeiitersat 267 the drum 265.

returns it to the sitter 120 and this material has to pass once more the rollers 32. rlhe material which has vpassed .the sieves ot the sitters 121 and 125V isled through the chute 312 to theslialring sieve v245y trom where it is ledtogethe'rsWith the material -which has passed through the sieve 244 `by Y thek chute 253 (Fig. 5) to the elevator 168 which teeds it directly to the'rollers 33 by Which-the iinal rough grinding is' finished.

F rom the rollers 33l thermaterial is conducted to the elevator 174 Vwhich delivers it to the sitter 111 at 131. rlhe material vwhich doesV not pass the sieveL ot the sitter 111 leaves the lat-ter at 132 and is conducted to the fine grinding rollers 40, tailsdown'V` i the chute 193 to the elevator '17 5 (Fig. 7

Which delivers at-136 to the sitter rlllie material leaving the latter `ate142 gets to the rollers 41,7then down the. chute 19.2 y l (Fig. 7')` to theelevator 173, at into the sitte`r 112, leaves the latter at 139 enters'.

Adirectly into the sitter 116 at 137, leaves the Y latter at 143 and gets tothe next roller passage42. From here theniaterial tails down the chute 191 to the elevator 172 and is "delivered by the latter-at 134 into the sitter 113, leaves the latterl at 1,40 to'be 'turther j treated by the rollers 43. 'i 4On leaving the time byjthe rollers 44.V The restot the treated materialv'talls down the veliutev1i89*V tothe elevator 170 `Which delivers it at 138 `to the sitter 117, it leaves the latter ai'. 144 The iine parts brushed through the drum are col lected at 268 as coarse meal. tor teeding animals andthe material which doesv not pasti the drum is collected at and consists ot Y clean bran. y

'T he finished meal, Which passes the sieves ot the sitters'111-117 is obtained in ltivo sieves ot the sitters 111, 112, and 116 is allowed to tall into the screivconveyor V201 `which delivers it to the opening 203V tor being filled into bags andthe meal passing the sitters 113, 114'Iand 117 gets into the' vscrevv conveyor 202 and at the opening 204 into bags. f

It will thus be seen that the tunction, ot the mill trom the time when the uncleaned grain is filled into` a hopper until the linished meal leaves the mill. is entirely automatic, no manual' labour being required during the conversion ot the grain into meal. This' conversion is obtained graduallyl and the material to be ground has to pass a comparatively large 'number ot consecutive grinding and disintegratino passages.

Every time betere the materia is subjected-` to a turther grinding action, it has to pass 'sitting device` which retains the parte et the material which are already sufiiciently v "ineand which do not krequire to pass the nextlgrinding passage. In this manner the grinding is effected very economically, little driving power is required," rst class prod- .iicts are obtained owing to the gradual Ygrinding action, which'inoreover converts every` particle of the grain, which c-anpossibly be so converted into meal.A Y l Thek number of passages for the-material to be ground may obviously be different to that described with reference'to the specific example.. 1' f I claim: Y f

l. In a self-contained automatic grinding mill, particularly for domestic use, lin combination; a number of cooperating indi-V vidual 'grinding rolls for rrough grinding,a number of cooperating individual grinding rolls forhne grinding, a set of :sifting means arranged above the roughy grinding rolls and cooperating with the latter, a secondk set ofsifting means arranged above the fine grinding rolls and cooperating with the latter, and means adapted to conduct the material toY be groundr consecutively to said y .grinding rolls for rough and fine grinding andto andfroinsaid sets of sifting means,

said'means includinga number of elevators arranged between saidroiigh grinding rolls and said line grinding rolls and to which the material leaving said 'individual rolls is conducted and kwhich deliversaidfmateiial t0 said sifting meansv arrangedA on Yboth vsides ofthe elevators.

conduct the material toV be ground consecu- Y tively to said individual pairs of rollers of both types` and to and ,from said sifters, said means including a plurality of elevators Yarranged in the middle portion of said chest, the material leaving said individual pairs of rollers beingy conducted to said' ele* vators which deliver the :material to sai-d sifters, some ofthe elevators discharging to lofthe sifters at one side of the casing and other elevators discharging. to the sifters on nthe other side'thereof.

3.111 an automatic grinding Y mill, inl

combination, a chest, rollers for i rough grinding rotatably mounted in the lowery part and to one side of the vertical centreV -plane of"y said chestjfand: subdivided into'k ya pluralityY of individual pairs of rollers rollers for finegrin'ding. rotatably mounted iiijthelower part tothe other vside of the vertical'V centre plane of said chest and subdivided into a plurality of individual pairs of rollers, a plurality of sifters ofthe centrifugal type'arranged vertically above said rollers forlrough grinding and a plurality ofisifters ofthe centrifugal type arranged Y vertically abovel said rollersffor fine grinding, shaking' sieves for cleaning thejmate-` rial to heV ground,y a strippingl devicef'for treating the ycleaned material received from Vsaid' sieves, and ineansto conduct the material to be ground consecutivelyto said' individual pairs of rollers of both types and to and from' said sifters, said'ineans including a lplurality ofv elevatorsarranged in the middle lportion ofsaid chest, the material leaving` said individual pairs offrollersfbeing 'conducted to said elevators which deliver theinateri'al to' said sifters, some of the elevators' discharging to the sifteisl on one side andf other Velevators dischargingjV tothe si'fters on the' other side of said casing.

binat'ion, a' chest, rollers for rough grinding rotatably mounted in the lovvv'eripart and to `one sidel ofthe vertical centre plane of said chest and subdivided 'into a 'plurality,ofA individual pairs yof rollers, a'pair ofl rollers for line grindingrotatably mounted inthe lower pai-'tto theyother side of tlievertical'ceI-itrev plane ofvsaid' chest,and :subdi ,vided intoa plurality of individual pairs of rollers,fa yplurality of sifters of the cei1- `trifugal type arranged vertically above Said rollers for4 rough kgrinding Aand a plu` rality of' sifter's ofthe centrifu individual pairsoffl rollers of both types and to and .from said sifters, saidmeans including a plurality of elevators arranged in two sets besidezea'ch other the middle fp'ortion" 0f said chest, thel materialwtobe treated'by the rough lgriii'ding rollers and lthe sifters on the same side of the chest be-V ing handled' bytheelevators of one set 'and the material to` be treated bythe fine grind'- ing rollers and Vthe sifters on the saine side of the chest being handled by the elevators Vof the other set..

5; In an automatic grindingmilhin com- Ual type ar-k ranged vertically vabove said rol 'ers for line 'vgrinding,` shaking sieves for cleaning the material to'v be ground, a stripping ydevice for treating n the cleaned material' received v,fromsaid,sie-ves", and means toconduct the materialito-be ground consecutively to lsaid fle In an automatic,grindingmillin.c`oin` Y bination, a chest, rollersfor rough grinding Y rotatably mounted inthe lower part and vto Vone side ofthe vertical centre plane of' said chest and subdivided into' a plurality,v

of individual' pairs of rollers,l rollersA for fat) fine grinding rotatably mounted in the lower part to the other side of the vertical centre plane of said chest, and subdivided into a plurality of individual pairs of rollers, a plurality of sitters of the centrifugal type arranged vertically above said rollers for rough grinding `and a plurality of sitters of the centrifugal type arranged vertically above said rollers for tine grinding, and means adapted to conduct the material to be ground consecutively to said individual pairs of rollers of both types and to and from said sitters, said means including a plurality of elevators arranged in tvvo sets beside each other in the middle portion of said chest, the material to be treated by the rough grinding rollers and the sitters on the saine side of the ehest'being handled by the elevators ot one set and the material to be treated by the line grinding rollers and the sitters on the same side of the chest being handled by the elevators ot' the other set, said meansv further including` tivo screw conveyors arranged below the sitters above the line grinding rollers, one of said conveyors receiving the finished meal passing through some of said sitters and the other receiving the finished meal of a different quality andl passing through the others of said sitters. y Y

6. ln an automatic grinding mill, in com'- bination, a chest, rollers for rough grinding rotatably mounted in the lower part and to one side ot' the vertical centre plane of said chest and subdivided into a plurality oi" individual pairs of rollers, rollers toriine grinding rotatably mounted in the lower part to the other side ot the vertical centre plane of said chest, and subdivided into a plurality of individual pairs ot rollers, a plurality oi sitters ot the centrifugal type arranged vertically above said rollers :tor rough grinding and a plurality of sitters of the centrifugal type arranged verticallyV above said rollers for fine grinding, shaking sieves for cleaning the material to be ground, a stripping device for treating the cleaned material received from said sieves, and means to conduct the materialV to be ground consecutively to said individual pairs oi rollers of both types and to and from said sifters,'said means including a plurality of elevators arranged in tivo sets beside each other 1n themiddle portion of said chest, tlie material to be treated by the rough grinding rollers and the sitterson the same side ot' the chest being handled by the elevators ot one set and the material to beV treated by the line grinding rollers and the Vsiiters on the same side ot 'thechest being handled by the elevators of theother set, a iilter plantv consisting of several'elements arranged on the top of said chest, and provided ivith an exhaust 'lian for removing the hot air inside the chest, and means -tor admitting fresh air to the interior ot the chest ing operations to a last stage ol' coarse` gv inding, subjecting the resulting semolina to successive tine grinding, sifting the material intermediate eachiine grinding, separating thelines from the fine grinding into graded flour, and grading the resultant coarseproduct, all of Which operations are automatically performed, from the entrance of the grain into the machine to the delivery `ot the `final products.

8. The method of grinding grain in a single apparatus, comprising cleaning the grain and rejecting the dirt, grinding the grain a plurality of times in a` plurality of successive coarse grinding operations, raising the material and sitting after each coarse ,grinding operation preparatory to regrinding, subjecting the resulting semolina` to successive tine grindings1 lifting the resulting materialandsitting it after each fine grinding, all the grinding steps being substantially at the saine level, and the ma? terial being raised from substantially the sie same level to substantially the same level,

and lVentilating along the paths of litt to maintain a current oit cooling air past the,

grinding points.V v

In testimony whereof I alliX my signature.

ALFRED., soHR.

iooY 

